docs: Fix Sphinx 3.x warnings, and enable warnings-as-errors on build.

This enables warnings as errors and fixes all current errors, namely:

- reference to terms in the glossary must now be explicit (:term:)
- method overloads must not be declared as a separate method or must
  use :noindex:
- 2 cases where `` should have been used instead of `

1 files changed, 2 insertions, 2 deletions

diff --git a/docs/library/index.rst b/docs/library/index.rst
index 7b1636ce6..952e67d43 100644
--- a/docs/library/index.rst
+++ b/docs/library/index.rst
@@ -23,7 +23,7 @@ into MicroPython. There are a few categories of such modules:
 * Modules which implement a subset of Python functionality, with a provision
   for extension by the user (via Python code).
 * Modules which implement MicroPython extensions to the Python standard libraries.
-* Modules specific to a particular `MicroPython port` and thus not portable.
+* Modules specific to a particular :term:`MicroPython port` and thus not portable.
 
 Note about the availability of the modules and their contents: This documentation
 in general aspires to describe all modules and functions/classes which are
@@ -38,7 +38,7 @@ in a module (or even the entire module) described in this documentation **may be
 unavailable** in a particular build of MicroPython on a particular system. The
 best place to find general information of the availability/non-availability
 of a particular feature is the "General Information" section which contains
-information pertaining to a specific `MicroPython port`.
+information pertaining to a specific :term:`MicroPython port`.
 
 On some ports you are able to discover the available, built-in libraries that
 can be imported by entering the following at the REPL::